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1.
The Southern Great Xing'an Range,Northeast China,is located in the eastern part of the Central Asian Orogenic Belt.It is considered to be one of the most important metallogenic belts,commonly hosting a series of skarn.porphyry and magmatic hydrothermal Pb-Zn-Ag-Cu Mo-Sn polymetallic deposits(Fig.1).Complex tectonic events have occurred in this region,including the closure of the Palco-Asian Ocean in the Late Palaeozoic,the opening and closure of the Mongol Okhotsk Ocean and the subduction of the Paleo-Pacific Ocean in the Mesozoic. 相似文献
2.
SONG Wanbing CUI Fanghu YANG Hongzhi ZHANG Li WU Xinwei SHI Jianmin ZHANG Chao 《《地质学报》英文版》2019,93(3):758-759
正Objective The Xing'an Block(XB) is located between the Erguna Block(EB) and the Songnen Block(SB), which topographically occupies the northeastern half of the Great Xing'an Range(Liu et al., 2017). The XB was traditionally considered to be composed of a Precambrian metamorphic basement and post-Cambrian cover. However, the recent geochronological studies show that the so-called "Precambrian metamorphic rocks" are much 相似文献
3.
DONG Yu GE Wenchun TIAN Dexin JI Zheng YANG Hao BI Junhui WU Haoran HAO Yujie 《《地质学报》英文版》2019,93(5):1500-1521
In this study, we present zircon U-Pb ages, whole-rock geochemical data and Hf isotopic compositions for the Meiguifeng and Arxan plutons in Xing'an Massif, Great Xing'an Range, which can provide important information in deciphering both Mesozoic magmatism and tectonic evolution of NE China. The zircon U-Pb dating results indicate that alkali feldspar granite from Meiguifeng pluton was emplaced at ～145 to 137 Ma, and granite porphyry of Arxan pluton was formed at ～129 Ma. The Meiguifeng and Arxan plutons have similar geochemical features, which are characterized by high silica, total alkalis, differentiation index, with low P_2O_5, CaO, MgO, TFe_2O_3 contents. They belong to high-K calc-alkaline series, and show weakly peraluminous characteristics. The Meiguifeng and Arxan plutons are both enriched in LREEs and LILEs(e.g., Rb, Th, U and K), and depleted in HREEs and HFSEs(e.g., Nb, Ta and Ti). Combined with the petrological and geochemical features, the Meiguifeng and Arxan plutons show highly fractionated I-type granite affinity. Moreover, the Meiguifeng and Arxan plutons may share a common or similar magma source, and they were probably generated by partial melting of Neoproterozoic high-K basaltic crust. Meanwhile, plagioclase, K-feldspar, biotite, apatite, monazite, allanite and Ti-bearing phases fractionated from the magma during formation of Meiguifeng and Arxan plutons. Combined with spatial distribution and temporal evolution, we assume that the generation of Early Cretaceous Meiguifeng and Arxan plutons in Great Xing'an Range was closely related to the break-off of Mudanjiang oceanic plate. Furthermore, the Mudanjiang Ocean was probably a branch of Paleo-Pacific Ocean. 相似文献
4.
<正>Objective The Great Xing'an Range is located in the eastern section of Central Asian Orogenic Belt(CAOB).As a superposed position of multiple tectonic domains,its structural evoIlution has always been a focused issue of geological research.The Triassic is a critical turning point 相似文献
5.
20110375 Lang Jiabin(Research Center of Paleontology and Stratigraphy,Jilin University,Changchun 130026,China);Wang Chengyuan Two Devonian Conodont Faunas from Onor Area in the Great Xing'an Range of Inner Mongolia,China(Acta Micropalaeontologica Sinica,ISSN1000-0674,CN32-1189/Q,27(1),2010,p.13-37,3 illus.,4 plates,85 refs.)Key words:conodonts,Inner Mongolia, 相似文献
6.
In this paper I shall attempt to describe briefly the Mesozoic strata occurring along the northern slope of the Ta Pieh Shan (大别山) range, i. e., the eastern extension of the Tsin Ling Range, for the purpose of discussing the date of the Tsin Ling folding. In regard to this point, geologists gave 相似文献
7.
In this paper I shall attempt to describe briefly the Mesozoic strata occurring along the northern slope of the Ta Pieh Shan (大别山) range, i. e., the eastern extension of the Tsin Ling Range, for the purpose of discussing the date of the Tsin Ling folding. In regard to this point, geologists gave 相似文献
8.
ZHANG Li LIU Yongjiang SHAO Jun LI Weimin LIANG Chenyue CHANG Ruihong YANG Hongzhi FENG Zhiqiang ZHANG Chao XU Ji SHI Yi YANG Fan HE Pengfei 《《地质学报》英文版》2019,93(5):1300-1316
There is a controversy regarding the amalgamation of Xing'an and Songnen Blocks along the Hegenshan-Heihe Suture(HHS) in the eastern Central Asian Orogenic Belt(CAOB). To solve this problem, we performed detailed study on the granites from the Zhangdaqi area, adjacent to the north of the HHS in the northern part of the Great Xing'an Range, NE China. Geochemically, the granites in the study area are metaluminous-weak peraluminous and high-K calc-alkaline series. Trace elements of the granites show that LREEs are relatively enriched, while HREEs are relatively deficient and obvious REE fractionation. The granites are characterized by obvious negative Eu anomalies, meanwhile, they are relatively enriched in Rb, K, Th and depleted in Ba, Nb, Sr, P, Ti. All the geochemical features suggest that the granites in the Zhangdaqi area are aluminum A-type granites. The zircon LA-ICP-MS U-Pb ages of these granites are 294–298 Ma, indicating that they formed in the Early Permian. These granites also have positive ε_(Hf)(t) values(8.4–14.2) and a relatively young two-stage model age between 449 Ma and 977 Ma, implying that the magma was derived from the re-melting of the Early Paleozoic-Neoproterozoic juvenile crust. Combined with geochemical characteristics(Nb/Ta ratios of 9.0–22.2, and Zr/Hf ratios of 52.3–152.0), we believe that the magmatic source area is a mixture of partial melting of the lower crust and depleted mantle. A-type granites and bimodal volcanic rocks along the Hegenshan-Heihe Suture formed during the Late Carboniferous-Early Permian, indicating that the HHS between Xing'an and Songnen Blocks closed in the late EarlyCarboniferous. Subsequently, the Zhangdaqi area was in a post-orogenic extensional environment from Late Carboniferous to Early Permian and resulted in the formation of the A-type granites. 相似文献
9.
WANG Chengyang LIU Guanghu SUN Zhenjun LIU Jie LI Jianfeng LIANG Xinyang 《《地质学报》英文版》2019,93(5):1522-1543
The Southern Great Xing'an Range(SGXR) hosts a number of Early Cretaceous Sn and associated metal deposits, which can be divided into three principal types according to their geological characteristics: skarn type deposits, porphyry type deposits and hydrothermal vein type deposits. Fluid inclusion assemblages of different types of deposits are quite different, which represent the complexities of metallogenic process and formation mechanism. CH_4 and CO_2 have been detected in fluid inclusions from some of deposits, indicating that the ore-forming fluids are affected by materials of Permian strata. Hydrogen and oxygen isotope data from ore minerals and associated gangue minerals indicate that the initial ore fluids were dominated by magmatic waters, some of which had clearly exchanged oxygen with wall rocks during their passage through the strata. The narrow range for the δ~(34)S values presumably reflects the corresponding uniformity of the ore forming fluids, and these δ~(34)S values have been interpreted to reflect magmatic sources for the sulfur. The comparation between lead isotope ratios of ore minerals and different geological units' also reveals that deeply seated magma has been a significant source of lead in the ores. 相似文献
10.
Late Mesozoic Thermotectonic Evolution of the Jueluotage Range,Eastern Xinjiang, Northwest China: Evidence from Apatite Fission Track Data 总被引：1，自引：0，他引：1
ZHU Wenbin WAN Jinglin SHU Liangshu ZHANG Zhiyong SU Jinbao SUN Yan GUO Jichun ZHANG Xueyun 《《地质学报》英文版》2008,82(2):348-357
Although many authors have emphasized the Cenozoic history of deformation, exhumation and cooling in the Tiaushan area related to the India-Asia collision, very little is known about the Mesozoic history of compression and uplift within the Tianshan. In order to obtain information about the Mesozoic exhumation history and processes of cooling in eastern Tianshan, fission track methods on apatite were used. Sampling was made in the Jueluotage Range. Three samples （Z001-Z003） were taken from granite in borehole ZK6301 of Yandong pluton; the ages range from 97.0 to 87.6 Ma that are much younger than the pluton age which was dated by U-Pb zircon at 334±2 Ma. Two samples in northern piedmont of the Jueluotage Range were collected from Jurassic strata in Dikaner （DK001） and Dananhu （D001） whose ages are 91.5 and 93.4 Ma respectively. The average apparent exhumation rate is 0.039 nun/a calculated by extrapolation on the basis of Yandong samples, indicating an extremely slow exhumation in the Jueluotage Range since the Late Cretaceous. Two Jurassic samples reached the maximum depths after deposition and experienced the maximum temperatures of ca. 105 and 108℃ until the late Early Cretaceous before a period of cooling and exhumation occurred at 114 and 106 Ma. 相似文献
11.
Guboglo M. N. 《GeoJournal》1980,4(1):53-58
International unity is becoming ever stronger in this country owing to an increasing similarity in the development of the cultural environment. This comprises the provision of all the country's republics with a sufficient number of schools, theatres, and other institutions and cultural information media in accordance with the needs of the population. An important part is played by the rise in ‘the general educational level, as well as the level of professional qualifications and skills. Among all the Soviet nations and nationalities, this rise being more rapid among formerly backward peoples. Prominent among the factors of internationalization is the progressive development of the nationalities’ cultural resources, while professional culture is being increasingly brought within the reach of the masses.The implementation of the nationalities policy promotes the all-round development of all Soviet nations and nationalities, their drawing together, the upsurge of the individual capabilities of every Soviet citizen. 相似文献
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13.
Chronological analyses of correlations between certain global repeating events (mass extinctions of marine organisms, meteorite impacts, and flashes in the frequency of geomagnetic reversals) during the Phanerozoic Eon and the motion of the solar system in the Galaxy are presented for five rotationally symmetrical models for the regular Galactic gravitational field. Thirteen of sixteen mass-extinction events can be described by a repetition interval of 183±3 million years. This is in agreement with the anomalistic period (interval between two subsequent passages of the Sun through the apocenter of its Galactic orbit) in the model of Allen and Martos. The positions of the minima and maxima in Gaussian functions approximating the frequency distribution for geomagnetic reversals also agree with the times of passage of the Sun through the apocenter and pericenter, respectively, of its Galactic orbit in this model. The maximum in the distribution of the deviations of the dates of mass extinctions from the nearest dates of impacts of large, crater-forming bodies is close to zero, providing evidence that many such events are correlated. As a rule, extinctions follow impact events. The impacts of large bodies have occurred most often when the solar system passes through the Galactic plane, while mass extinctions occur more often at some distance from the Galactic plane (about 40 pc). As a rule, intervals of increases in the frequency of geomagnetic reversals coincide with dates of impacts of large bodies. At the same time, these intervals do not show a clear correlation with the dates of mass extinctions. The intensity of mass extinctions, like the energy released by impacts, is consistently higher in periods when the Sun is moving from the apocenter toward the pericenter of its orbit, than when it is moving from the pericenter toward the apocenter. Thus, there is evidence for a variety of relationships between repeating global events in the Phanerozoic and the motion of the Sun in the Galaxy. Long-period variations in the frequency of geomagnetic reversals are correlated with the orbital motion of the Sun, and increases in the frequency of geomagnetic reversals are correlated with impacts. Mass extinctions are correlated with the impacts of large bodies, whose motions may have been perturbed by clouds of interstellar material concentrated toward the Galactic plane and by the shock front associated with the Perseus spiral arm, through which the solar system passes. The velocity of the Sun relative to the spiral pattern is estimated. 相似文献
14.
Deviation of the major axis of the inertia ellipsoid of the Moon from the direction toward the Earth
B. P. Kondratyev 《Astronomy Reports》2017,61(8):709-714
It is known from observations that the center of mass of the Moon does not coincide with the geometric center of its figure, and the line connecting these two centers is not aligned with the direction toward the center of the Earth, instead deviating toward the Southeast. This stationary deviation of the axis of the inertia ellipsoid of the Moon to the South of the direction toward the Earth is analyzed. A system of five linear differential equations describing the physical libration of the Moon in latitude is considered, and these equations are derived using a new vector method taking into account perturbations from the Earth and partly from the Sun. The characteristic equation of this system is obtained, and all five oscillation frequencies are found. Special attention is paid to the fifth (zero) frequency, for which the solution of the latitude libration equations are stationary and represents a previously unknown additional motion of the rotational axis of theMoon in a cone with a small opening angle. In contrast to the astronomical precession of the Earth, the rotation of the angular-velocity vector is in the positive direction (counter-clockwise), with the period T 3 = 27.32 days. On this basis, this phenomenon has been named “quasi-precession.” This quasi-precession leads to a stationary inclination of the major axis of the inertia ellipsoid of theMoon to the South (for an observer on Earth), making it possible to explain one component of the observed deviation of the center of mass of the Moon from the direction toward the Earth. The opening angle of the quasiprecession cone is approximately 0.834″. 相似文献
15.
位于华北和扬子两板块碰撞带中的苏鲁榴辉岩形成的温压条件不但是超高压，而且是高温。榴辉岩的PTt轨迹表明其为陆-陆磁撞俯冲带的产物。榴辉岩的区域性围岩花岗质片麻岩为新元古代同碰撞期花岗岩，榴辉岩及其他直接围岩皆呈包体存在于其中，并见新元古代花岗岩呈脉状侵入榴辉岩包体中。区域性围岩新元古代花岗岩的锆石中发现有柯石英、绿辉石等包裹体，表明新元古代花岗岩的组成物质也经受过超高压变质作用，且榴辉岩与围岩新元古代花岗岩的锆石U-Pb体系同位素年龄基本相同。但新元古代花岗岩所记录的变质作用和变形作用期次（或阶段）却少于榴辉岩。椐上述可得如下推断：超高压榴辉岩与新元古代花岗岩岩浆是同时在碰撞带底部（俯冲板块前部）形成的；榴辉岩的第一折返阶段是由新元古代花岗岩岩浆携带上升的，其第二折返阶段是和新元古代花岗岩一起由逆冲及区域性隆起而上升，遭受剥蚀。 相似文献
16.
17.
摩擦桩基桩土间极限摩阻力取值问题探讨 总被引：1，自引：0，他引：1
通过对广珠东线高速公路横沥大桥的试桩及土体的工程地质条件分析,总结出影响摩擦桩基桩土间极限摩阻力取值的一般问题以及解决问题的方法和措施。 相似文献
18.
某高速公路下伏煤矿采空区稳定性分析 总被引：10，自引：0，他引：10
在论述某高速公路下伏砦脖煤矿采空区地质、采矿和工程地质特征的基础上，进行了稳定性数值模拟分析，定性与定量地分析与评价了该煤矿采空区的地表变形特征及稳定性。研究结果表明：该煤矿采空区的变形尚未完成，对拟建的高速公路将产生很大的危害，必须采取相应的工程治理措施。 相似文献
19.
The structure of the eastern Pyrenees consists mainly of south-directed thrusts involving basement and cover rocks. An antiformal stack developed by the piling up of basement thrust sheets which outcrop in the Axial zone. These structures account for a thin-skinned thrust model rather than a vertical fault model in which the Axial zone would be essentially autochthonous, and the North-Pyrenean fault the axial plane of a fan thrust system. New data from the Eastern Pyrenees and the thin-skinned model suggest that(1) the structure east of the Pedraforca nappe is similar to that of the Central Pyrenees; (2) the cover rocks of the South-Pyrenean units and of the Axial zone-after restoration—built up a northwards-thickening prism consistent with the existence of a unique Pyrenean sedimentary basin during Mesozoic time; (3) the Axial zone is only a complex antiformal stack developed as a part of South-Pyrenean system related to the Paleogene thrusting-tectonics. The Axial zone palaeogeographic area had no special meaning during Mesozoic time. 相似文献
20.
Michel Westphal Mikhail L. Bazhenov Jean Paul Lauer Diamar M. Pechersky Jean-Claude Sibuet 《Tectonophysics》1986,123(1-4)
We first re-examined the apparent polar wander curves for stable Eurasia and Africa since the Triassic. These curves were then combined together with curves of North and South America according to the kinematics of the Atlantic ocean and a synthetic polar wander curve was given. Then, most of the paleomagnetic results from the Tethys mobile belt, from the Atlantic to the Pamirs, were analysed.Several groups of plates, microplates and blocks can be seen. First, relatively stable regions like Maghreb and Sicily, which have not moved much. Then we have a group formed by Iberia, Sardinia, Italy and, to a lesser extent, Corsica and the Western and Central Alps. For these blocks, movements are anticlockwise rotations chiefly driven by the anticlockwise rotation of Africa, but they are sometimes stronger.To the east, a major change takes place. The north of the Aegean Sea and the Ionian zone are clockwise rotated and these rotations are recent: Oligocene-Miocene for the first part, Pliocene to the present for the second part.A major problem arises in Turkey, Caucasus and Iran. Paleomagnetic results indicate a position far to the south of Eurasia, and, at the same time, geological evidence is in favour of a position close to Eurasia. We discuss these discrepancies. 相似文献